Artificial hand



March 14, 1950 c, LOHMANN 2,500,614

ARTIFICIAL HAND riled Jan. 14, 1948 2 Sheets-Sheet 21 INVENTOR. CARL LOHMANN Patented Mar. 14, 1950 UNlTED STATES PATENT OFFICE ARTIFICIAL HAND Carl Lohmann, New York, N. Y.

Application January 14, 1948, Serial No. 2,182

5 Claims. 1 This invention relates to new and useful improvements in artificial limb constructions, and, more particularly, aims to provide a novel and valuable artificial hand. v

According to the present invention, ball and socket joints are provided at the knuckle loca-- tions, arranged so that any one or more of the fingers may be variously adjusted as desired and so that when thus adjusted they will remain in their adjusted positions. Preferably, detent means are partially carried by each of the ball and socket elements of a joint, and means are present for limiting relative movement of the parts at the joint, to restrain swinging movement of one part of a joint relative to another part of that joint in such manner that said swi ng ing is always a rotative one aboutfa "single axis. Members si'niulating the bones of a human finger and the bone at the root ofthe finger of the human hand are provided, between which members said joints are interposed. Said members are shaped to provide top channels extending lengthwisely of the members, these channels specially shaped for coaction with an endw'isely movable member, preferably a long leaf spring resiliently biased to longitudinal curvature. 'The means provided by this spring and said channels is effective to curl or bend inward, toward the palm of the hand, the finger served by said means,

or each of as many fingers as are so served, when, in regard to its associated finger, saidv spring is endwisely advanced to traverse all the channels one after another.

As the invention is herein shown and described, said spring is always partially inserted into the hand, that is, under the skin-simulating sheath thereof, and into the channel of that one of the bone members of the associated finger corresponding to the phalange of a natural finger at the inner end of the latter. In rear of such entry of the spring into the hand, the spring extends along the back of the hand and is housed in a guiding and holding track preferably having a substantially fiat bottom. With the one or more springs in retracted position, that is, only partially inserted into the hand as above, the fingers of the artificial hand can be manually adjusted as desired, as by the use of the other hand. When a spring is endwisely advanced, by use of the other hand, the finger associated with that spring is completely curled or bent inward toward the palm of the artificial hand, as for grasping an article.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawing, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure:

Fig. 1 is a view, partially in side elevation and partially in section, showing in full lines the wrist portion and a straight extended finger of an artificial hand pursuant to the invention, also outlining in dot and dash other parts of said hand.

Fig. 2 is a detail sectional view, taken on the line 22 of Fig. 1.

to Fig. 1, but sho 'il i n ing an article;

Fig. 5 is a perspective view of the spring, per se. Fig. 6' shows in perspective one of the ball and 'socket carrying members which extend between knuckle and knuckle of said finger.

, Fig. 7 is an enlarged sectional view, showing one of the ball and socket joints.

The artificial hand, according to the present invention, includes a plurality of flexible fingers; however, the details of the construction are illustrated in connection with the index finger I! only. It is to be understood that those constructional details apply equally well to each of the other fingers of the artificial hand; such as the finger l5 and the thumb l6, shown in'dot and dash lines in Fig. 1.

The index finger ll includes a sheathing ill for simulating the skin of the human hand, within which sheathing are articulated bone members I9, 20, 2| and 22, made of aluminum, plastic or some other suitable and preferably light and strong material, for simulating the equivalent bones of the human index finger.

Ihe bone member I9 is shown as extended at l9 to form a part of the wrist and also to back up the relatively stiff padding or other filler, not shown, for shaping the sheathing l8 at the palm of the hand.

The bone member [9 at its forward end carries a spherical socket 23 within which is pivotally but irremovably seated a ball 24 formed at the rear end of the bone member 20. The bone member 20 at its forward end carries a spherical socket 25 within which is pivotally but irremovably'seated a ball 26 formed at the rear end of the bone member 2|. The bone member. 2|

modem at its forward end carries a spherical socket 21 withinwhich is pivotally but irremovably seated a ball 28 formed at the rear end of the bone member 22. These ball and socket joints between the bone members thus represent the knuckles of the finger of the human hand. The balls are irremovable from their sockets because the sockets have their rims in a plane marking oiT slightly, more. than one-half the. .bulk ofv the associated balls inlany possible.angularrdiseposition of the ball relative to its socket.

Means is provided to prevent lateral pivoting of the balls in their respective sockets and so. limit the ball members 20, 2! or 22 tos'swingl: vertically up and down, or toward andaway from. the palm of the hand. Referring in this con nection particularly to Figs. 6.1andfl,twhere;.in; order not unduly to add to the drawings, the;

the rear end of the channel, first rising according to a straight line slope to a convexly curved crest and then continuing as a curvilinearly descending final portion, to correspondingly deepen the channel, as shown very clearly in Fig. 6. As will further be noted, the channel 45 along the top of the bone member 22 has a first generally curvilinearly rising bottom and then a. straighttbottom. terminatedlby.an... end wall 46. It'fshouldialso the IIOlJGdJlihQlSLWilll'Y-ihG parts as in Fig. 1, the rear end of the channel 43 at its 1 bottom is at a lower point than the forward end arrangement provided for each of the ball and socket joints is shown only in connection with the-- joint betweenthe -bone-members and 2 I 5 lih'G'SOGkBll-{Z 5 has anarcuate keyway 2 fl withirr whichis? endwisely' slidable" an arcnatee keyfixedly carried by-'"tl'i'e'ball -:26.'-'

In orderto-permit th'e =bone member 21 to-be releasably held in any one-of a pluralitwot ad j =us.ted positions-on" the' bone member 10*, a de.- tent means-'isfprovid'ed'. The detent means-com= prises an arcuateline of' recesses 3'! formed in therso ck'et' 2 5}as a prolongation of the keyway; 2 9': A small ball 32- forengaging anyoneof there-'- cesses 3| aligned with the ball is projectedfrom 3RW61'P3WiII the ball 26"b'y 'a light spring 33. A precisely similar arrangement'isprovided'in com nectio'rr with theballa-nd socks?"joints-235%.

ahd;.2'[.--28;. but preferably very with therecesses-r corresponding. tor-the essejsgfil prosvidedrfonthezsocketfi1 toiarlessenumb'eit-tlian-said: recesses -as provided' for thesocket+ 25.-and 'ffor1 the socket 23.

The under portions of the-bone membersz zll, 21* and-222* "are suitablvshaped by fillers -351 of densepadding formed of sponge-' rubber or the like material; To-- allow bending of the -finger,- as fromthe condition" shown; in Fig. 1 to that shown in Fig. 4, theysheathing I B'should'be some"- what "elastically :stretchablealong the length of the finger, particularly; between r filler; blocks" 36; 31; 38* and 39 which are formed of aluminum; plastic or theliker The-filler blocks; havetl'ie cross secti-on-illustratedfin Fig; 3*in; theq-case of the block 13 6 f on assisting in giving the-artifi' cial=fiiiger a natural lateral roundness at its, up per portions.

These; blocks overlie and close intermediate portions of channels extended along thetops" of the membersm -ZU, 21 and 22: ;Allof"tlie-chan nelsare of-the same-width; about the width indicated in Fig. 3 for the channel dfl 0f the -bone member I 9 As-- w-iiI' be-'-- noted ,2 the; channel 1 40-; f1 0m= the point 4|, where-said channel has-an endafignedwithan-openi-ng in the sheathing I 8; hasdts-bottomextending forwardly substantially "along astraight line, until"- such bottom dovvnvvardly' curvilinearly dips at 42;: to -correspondingly'vari=- ously deepen said channel. Als'o asw ill be noted'; thexchannel 43 a1ong the topof tlie bone memb'er:20ihas itsbottom, startingfrom the' rear end of said member; first curvilinearlyarising: and then curvilinearlydescending, according: to a somewhat symmetrical convexity, to correspond ingly variously deepen 'said 'chan'nel. Also -as will-b'e-noted; the channel allti valong:the:=to1; :otthe b'onew'memberrfl' has its: bottom;.--startirig: from of thevbottom of the channel c6, and that the reanend of the channel 44 at its bottom is at a lolwer npointtthan the forward end of the channel 43 at its bottom, and that the rear end of 'tlie--cl'iannel"45=*at its bottom is at a lower point thangthe highest point of the bottom convexity of the channel 44.

Thegchannel featuresjust. described,,assisted bythesmooth under, sides; of =tlie blocks .3613], llll andlffllr where. said blocks" overlie the-channels. allow a single long leaf spring- '41;.nor mally having. its..forwa-r.d .portion .in ;substantia1ly -..the. entirety of .thechannelA l, .tobeendwisely forward= lyi moved first. to, enter and pass... through. the channel 43, next stopenterhand, pass through,..the channel :44; and-mextioenter andipass. .allamng the channfl. 45 uhtil. the. forward end .of, said sppi-ngeabutsea ainst .theendgwall .46.

The-spring is.;r.esiliently .set-so. fiSiQ-IGSH? ient1y.-.assumet a .=.cur vilinear lines of lengthwise extension, -;a hown-linlFig fi. The resilienttbias and socket-.jointscto the; redispositionsxshownsin Fig:;,4-fromzthoseashoyvn'in Fig. 1. Nevertheless; thegresilient ibiasiOfgsaid springa-is-wnot such-was to makewtheespringe'smstiifi-that; when withdrawn toath'eextent-sshowneimiFig. '1 forzfullinormaleree turn :into amtoragevtrack 432 having lJh'B cross::sectionzzshowmzin Fig. 2;: and: having itsrbottom straighti-'thea spring: :cannot-tueasil y.be:- drawn; stoflat?.condition cthroughout';- that portion of; its; lengthawithdrawnrfromrthe finger 11 for housing imsaida'track. 1

TIieetrackMB-Jlis; suitably-secured to; :theloacki-of the hand, in line Withlthev channel: 40; The length of: that .zpartzaofthe: spring housed; in the trackx48: when r'th form'eri-isretractedfito. the 6X'-'-.' tentrshow-n rim Fig.1; 1: is diagrammatically indie cated in Fig: 5* as extending between 1 a terminal upturned lip 49 on the spring and the dot and dashline 50;

The lip' 49" may have a string-'or cord fil connected thereto by way of an aperture- 521mm through; for: retracting the spring, to allow the hand toi'b'e arranged as inFi'g; 1.' The spring is also shownas carry-ing a handle projection 53; sogthat by use-of the=other hand to grip the projection the spring may: be extended into the -artificial"finger ,-to cause the-finger lT'to-be arranged a's=-in1F-i'g-.-l.- Such-projection can also 1 be used to retract the spring; whereupon thefinger ['1' may bewrearranged' as in Fig: 1 by: pressing the tip of the finger-to a table top on-the like.

The=nelements 3fh-34 may be omitted; or=retained for holding the finger l l as directly man ually adjusted as 1 above X explained; in :whichi-ilatten connection:- it:..will he understood that. such eeman arrangement of the fingers, each is provided with i I a simulated fingernail 54 set in and suitably secured to and exposed through the sheathing i8.

While I have illustrated and described the preferred embodiment of my invention, it is to be understood that I do not limit myself to the. pre-' cise construction herein disclosed and the right is reserved to allchanges and modifications coming within the scope of the invention as defined in the appended claims. v

Having thus described my invention, what I claim as new, anddesire to' secure by United States Letters Patent is:

1. In an artificial hand, a plurality of elongated bone members arranged in end alignment" and simulating the bones of one of the fingers of the human hand and the bone of the human hand at the root of the said finger, sockets formed at the front ends of each of said bone members except the bone member simulating the bone at the tip of the finger of the human hand, balls formed at the rear ends of each of said bone members except the bone member simulating the bone at the root of the finger of the human hand, the balls of the bone members being pivotally engaged in the sockets of the next adjoining bone members, means limiting pivoting of said bone members relative to each other to a plane extended at right angles to the plane of the palm of the hand, said bone members being formed along their tops with end aligned channels, means removably inserted into said chan" nels for holding said bone members pivoted relative to each other toward the palm of the hand, and means for individually holding each of said bone members in a desired pivoted position relative to its adjacent bone member when said removable means is withdrawn from said channels.

2. In an artificial hand, a plurality of elongated bone members arranged in end alignment and simulating the bones of one of the fingers of the human hand and the bone of the human hand at the root of the said finger, sockets formed at the front ends of each of said bone members except the bone member simulating the bone at the tip of the finger of the human hand, balls formed at the rear ends of each of said bone members except the bone member simulating the bone at the root of the finger of the human hand, the balls of the bone members being pivotally engaged in the sockets of the next adjoining bone members, means limiting pivoting of said bone members relative to each other to a plane extended at right angles to the plane of the palm of the hand, said bone members being formed along their tops with end aligned channels, means removably inserted into said channels for holding said bone members pivoted relative to each other toward the palm of the hand, and means for individually holding each of said bone members in a desired pivoted position relative to its adjacent bone member when said removable means is withdrawn from said channels, said pivot limiting means comprising a key formed on each of said balls, and the material of said bone members forming said sockets being formed with keyways into which said keys are slidably extended.

3. In an artificial hand, a plurality of elongated bone members arranged in end alignment and simulating the bones of one of the fingers '6 a of the human hand and the bone of the human hand at the root of the said finger, sockets formed at the front ends of each of said bone members except the bone member simulating the bone at the tip of the finger oi the human hand, balls formed at the rear ends of each of said bone members except the bone membersimulating the bone at the root ofthe fingerof the human hand, the balls of the bone membersbeadjoiningbone members, means limiting pivoting of said bone members relative" to veach'other to a plane extended at right angles to the plane of the palm of the hand, said bone members being formed along their tops with end aligned channels, means removably inserted into said channels for holding said bone members pivoted I relative to each other toward the palm of the hand, and means for individually holding each of said bone members in a desired pivoted position relative to its adjacent bone member when said removablemeans is withdrawn from said channels, said first-mentioned holding means comprising an elongated flexible spring extended into said grooves, said spring having'a set to assume a curved shape for holding said bone members pivoted relative to each other toward the palm of the hand.

4. In an artificial hand, a plurality of elongated bone members arranged in end alignment and simulating the bones of one of the fingers of the human hand and the bone of the human hand at the root of the said finger, sockets formed at the front ends of each of said bone members except the bone member simulating the a bone at the tip of the finger of the human hand, balls formed at the rear ends of each of said bone members except the bone member simulating the bone at the root of the finger of the human hand, the balls of the bone members being pivotally engaged in the sockets of the next adjoining bone members, meansv limiting pivoting of said bone members relative to each other to a plane extended at right angles to the plane of the palm of the hand, said bone members being formed along their tops with end aligned channels, means removably inserted into said channels for holding said bone members pivoted relative to each other toward the palm of the hand, and means for individually holding each of said bone members in a desired pivoted position relative to its adjacent bone member when said removable means is withdrawn from said channels, said first-mentioned holding means comprising an elongated flexible spring extended into said grooves, said spring having a set to assume a curved shape for holding said bone members pivoted relative to each other toward the palm of the hand, and a track mounted along the top of the bone member simulating the bone at the root of the finger of the human hand to receive and retain, said spring when withdrawn fromsaid channels.

5. In an artificial hand, a plurality of elongated bone members arranged in end alignment and simulating the bones of one of the fingers of the human hand and the bone of the human hand at the root of the said finger, sockets formed at the front ends of each of said bone members except the bone member simulating the bone at the tip, of the finger of the human hand, balls formed at the rear ends of each of said bone members except the bone member simulating the bone at the root of the finger of the human hand, the balls of the bone members being pivotally ing pivotally engaged in the sockets'of the next 

